Effect of Trace Doping Ce Element on Microstructure, Texture and Magnetostrictive Behavior of Polycrystalline Fe81Al19 Alloys

Abstract:

Fe-Al alloys exhibit excellent mechanical properties, low cost, and moderate magnetostriction, making it a promising magnetostrictive material. The polycrystalline (Fe₈₁Al₁₉)_100-xCe_x (x=0, 0.05, 0.10, 0.20, 0.30, 0.40, at%) alloys were prepared by arc melting. The effect of trace doping rare earth elements Ce on the microstructure, texture, and magnetostrictive behavior of Fe₈₁Al₁₉ alloys was investigated. Results show that the trace doping of the Ce element transforms the equiaxed crystals into columnar crystals, thus significantly improving the volume fraction of favorable η texture. The columnar crystal characteristics gradually weaken with the increase in Ce content, leading to weakening of η texture and an increase in the volume fraction of α and γ texture. With the increase in Ce content, a large amount of Ce-rich phases form at grain boundaries and within the grains. Among them, the phases at grain boundaries are mainly composed of Ce-Al-rich phases, while the phases within the grains is a composite secondary phase of Ce-Al wrapped around the Fe-Ce-rich phase. The magnetostriction of Fe₈₁Al₁₉ alloy is significantly enhanced by trace doping of Ce element. The peak magnetostriction of 153 ppm is obtained at the Ce element of 0.05at%, with an enhancement of 89% compared to the magnetostriction of a binary alloy. This improvement in magnetostriction is attributed to more columnar crystals containing η textures and the formation of more nanoheterogeneous phases owing to solid solution of trace Ce element .